Composition and method for selective herbicide

ABSTRACT

An environmentally safe selective herbicide is provided that includes at least one metal component and at least one chelating agent. The metal component can have a variety of forms, but is preferably in the form of a metal salt, a metal chelate, or combinations thereof The chelating agent can also have a variety of forms, but is preferably in the form of a metal chelate, a salt, an acid, or combinations thereof Methods of use are also provided. In another embodiment, an improved selective herbicide, as well of methods of controlling unwanted plants using such a herbicide, are provided. A method for treating undesired vegetation can include providing a selective herbicidal composition that includes a water-soluble selective auxin-type herbicide and a chelating agent complexed with at least one transition metal, and contacting vegetation with a herbicidally effective amount of the composition such that unwanted vegetation is controlled, while desired vegetation is unaffected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/686,098 filed on Mar. 14, 2007 and entitled “Enhancers For Water Soluble Selective Auxin Type Herbicides,” which is a continuation-in-part of U.S. patent application Ser. No. 11/252,192 filed on Oct. 17, 2005 and entitled “Composition and Method for Selective Herbicide” (now abandoned), which is a continuation of U.S. patent application Ser. No. 10/374,643 filed on Feb. 26, 2003 and entitled “Composition and Method for Selective Herbicide” (now U.S. Pat. No. 6,972,273), which claims priority to U.S. Provisional Patent Application No. 60/361,217 filed on Mar. 1, 2002, all of which are expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to selective herbicide compositions, water-soluble selective auxin-type herbicides, and methods for controlling unwanted vegetation.

BACKGROUND OF THE INVENTION

The control of unwanted vegetation is a continually important effort as it is needed for reducing health problems, such as allergies, the removal of poisonous/noxious weeds, increasing crop productivity, as well as improving the general aesthetics around the home. Unwanted vegetation can be controlled using herbicides that are either selective or non-selective. Non-selective herbicides kill or damage all plants to which they are applied, i.e., both desired and undesired vegetation. In contrast, selective herbicides eliminate or inhibit the growth of unwanted vegetation, while leaving the desired vegetation relatively unharmed. Contact herbicides are applied to the top growth, or portion(s) of the plant located above the soil surface. These herbicides, which kill or damage the top-growth only, are typically effective on annual weeds or vegetation. In contrast, systemic herbicides are initially taken up by the roots and/or the foliage of the plant and subsequently translocated to tissues that are remotely located from the point of application.

An example of a commonly used non-selective herbicide is glyphosate, marketed under the trade name Roundup®, among others, which kills all vegetation it contacts. An example of a well-known auxin-type selective herbicide is 2,4-dichlorophenoxyacetic acid (also known as “2,4-D”), which is commonly used for the removal of broadleaf weeds growing in grass and turf.

There are a variety of selective herbicides that are available on the market for the selective control of grass and broadleaf weeds growing in a variety of crops. The majority of these herbicides are synthetic compounds, with some herbicides raising concerns in recent years as to their safety to humans and the environment in general. Within the context of postemergent broadleaf weed control in grass, auxin-type herbicides are commonly used. There are four main families of synthetic auxin-type herbicides available on the market, including: the phenoxyacetic acid or phenoxyalkanoic acid family (e.g. 2,4-D), the benzoic acid family (e.g. dicamba), the pyridine carboxylic acid or picolinic acid family (e.g. triclopyr), and the quinolinecarboxylic acid family (e.g. quinclorac). These auxin-type herbicides are systemic compounds that have activity against a number of broadleaf weeds including perennial species. A number of registered products exist with these compounds, some using the individual compounds alone while others have two or three combined together (e.g., Killex® contains 2,4-D, mecoprop and dicamba).

The Phenoxy Acid-Type selective herbicides include 2,4-D (2,4-Dicholorophenoxyacetic acid), 2,4-DP (2,4-Dicholorophenoxypropionic acid, or Dichlorprop), and mecoprop (2-(2-methyl-4-chlorophenoxy) propionic acid). These systemic selective herbicides are initially taken up by the leaves, stem or roots of a plant, and subsequently moved throughout the plant. 2,4-D and 2,4-DP stimulate nucleic acid and protein synthesis and affect enzyme activity, respiration, and cell division, while mecoprop affects enzyme activity and plant growth. The Benzoic Acid-Type selective herbicides include dicamba, another systemic selective herbicide that is initially taken up by the leaves and roots of a plant and subsequently moved throughout the plant. Benzoic Acid-Type selective herbicides are similar to the Phenoxy Acid-Type selective herbicides described above.

A drawback of the synthetic auxin-type herbicides is their slow speed of activity. Often herbicidal activity is not seen for several weeks after application. Moreover, the products that are available for use by homeowners often do not result in adequate weed control with one application, resulting in the need for additional applications in order to achieve acceptable weed control.

Currently, these selective herbicides present major toxicological and environmental concerns. Attempts have been made to create selective herbicides that are effective, yet environmentally safe. Smiley (U.S. Pat. No. 6,323,153) teaches using various salts of chelating agents that are capable of forming stable coordination complexes with calcium and magnesium salts to control the growth of various weeds in lawns. In another patent (U.S. Pat. No. 6,117,823), Smiley discloses the use of aliphatic carboxylic acid diesters, such as dimethyl succinate and dimethyl glutarate, as non-selective herbicides. Simpson (U.S. Pat. No. 6,258,750) teaches an algaecide, herbicidal and/or fungicidal composition including a metal, the chelating agent, ethylene diamine disuccinic acid (EDDS) or a salt thereof, and a source of calcium and chloride ions. Hudetz (U.S. Pat. No. 6,271,177) teaches a herbicide that combines a sulfonyl urea compound and a water-soluble iron compound, while Sedun (WO 01/50862) discloses a herbicidal composition containing a combination of maleic hydrazide (MH) and carboxylic acids. Sedun also discloses that MH may be combined with an amine salt of a carboxylic acid (e.g., triethanolamine salts), which is chemically distinct from compounds that include amine and carboxylic function groups on the same molecule (e.g., EDTA).

Thus, there is presently a need for safer alternatives to currently used selective herbicides. There also exists a need for an environmentally safe selective herbicide that can selectively control unwanted plants, grasses and weeds, while leaving other plants and crops relatively unharmed. There is also a need in the art for novel methods and compositions for the improvement and enhancement of selective auxin-type herbicides that will benefit both consumers and the environment.

SUMMARY OF THE INVENTION

The present invention is directed to an environmentally safe selective herbicide that includes at least one metal component and at least one chelating agent. The metal component can have a variety of forms, but is preferably in the form of a metal salt, a metal chelate, or combinations thereof. The chelating agent can also have a variety of forms, but is preferably in the form of a metal chelate, a salt, an acid, or combinations thereof. Methods of use are also provided.

The disclosed herbicidal compositions can be made as a ready-to-use composition, a liquid concentrate, or a dry concentrate. Plants such as lawn grasses remain relatively undamaged by the disclosed compositions, whereas unwanted plants such as dandelions (Taraxacum officinale), daisies (Bellis perennis), chickweed (Stellaria media), mosses, liverworts, algae are severely damaged or killed by the disclosed compositions.

The present invention is also generally directed to methods and compositions for an enhanced water-soluble selective herbicide. In particular, the present invention provides an enhanced and/or synergistic, effective, fast-acting, long-lasting water-soluble selective herbicide that will remove unwanted broadleaf weeds from grass and turf. In one embodiment, an exemplary method for treating undesired vegetation can include providing a selective herbicidal composition that includes a water-soluble selective auxin-type herbicide and a chelating agent complexed with at least one transition metal, and contacting vegetation with a herbicidally effective amount of the composition such that unwanted vegetation is controlled, while desired vegetation is unaffected.

In one aspect, the exemplary method can provide a selective herbicidal composition that includes a water-soluble selective auxin-type herbicide in the form of an acid, an ester, a salt, and combinations thereof. The metal component of the composition can be a transition metal selected from the group consisting of copper, iron, manganese, zinc, and combinations thereof. The chelating agent component of the composition can be a chelating agent selected from the group consisting of an aminopolycarboxylate, an amino acid, a salicylate, and combinations thereof.

In another embodiment, an exemplary method for treating undesired vegetation involves providing a herbicidal composition that can include a water-soluble selective auxin-type herbicide and an ethylenediaminedisuccinic compound, and contacting vegetation with a herbicidally effective amount of the composition such that unwanted vegetation is selectively controlled, while desired vegetation is undamaged.

In one aspect, the exemplary method can provide a herbicidal composition wherein a ethylenediaminedisuccinic compound is in the form of an acid or a salt. When the ethylenediaminedisuccinic compound is a salt, it is selected from the group consisting of sodium salts, potassium salts, ammonium salts, and combinations thereof.

Unless otherwise noted, all percentages referred to herein are percent by weight.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

In one embodiment, the present invention provides an environmentally compatible, selective herbicidal composition comprising a combination of a metal component and a chelating agent. The metal component of the formulation can be in the form of a metal salt, a metal chelate, or combinations thereof, and the chelating agent can be in the form of a metal chelate, a salt, an acid, or combinations thereof.

The metal component of the present invention can include a variety of metals, but preferably includes a transition metal ion. Suitable transition metal ions include, for example, copper ions, iron ions, manganese ions, nickel ions, zinc ions, and combinations thereof. In an exemplary embodiment, the metal component includes an iron ion. The metal ions can be added in a variety of ionic states. By way of non-limiting example, iron ions used in the present invention can be added as either Fe⁺² ions, Fe⁺³ ions, and mixtures thereof.

The metal component of the present invention can also be added in a variety of forms. In one embodiment, the metal ions can be added as a metal salt. Preferably, when the metal ions are added as a salt, they are added as metal chlorides, metal sulfates, metal nitrates, metal citrates, metal phosphates, metal chelates, metal sulfides, metal sulfites, metal succinates, metal gluconates, metal lactates, metal formates, metal nitrites, metal salicylates, metal carboxylic acids, and in combinations of these salts.

In another embodiment, the metal ions can be added to the herbicidal composition as a metal chelate. A variety of chelating agents can be used in the selective herbicide compositions of the present invention to form a metal chelate. By way of non-limiting example, suitable chelating agents include aconitic acid, alanine diacetic acid (ADA), alkoyl ethylene diamine triacetic acids (e.g., lauroyl ethylene diamine triacetic acids (LED3A)), aminotri (methylenephosphonic acid) (ATMP), asparticaciddiacetic acid (ASDA), asparticacidmonoacetic acid, diamino cyclohexane tetraacetic acid (CDTA), citraconic acid, citric acid, 1,2-diaminopropanetetraacetic acid (DPTA-OH), 1,3-diamino-2-propanoltetraacetic acid (DTPA), diethanolamine, diethanol glycine (DEG), diethylenetriaminepentaacetic acid (DTPA), diethylene triamine pentamethylene phosphonic acid (DTPMP), diglycolic acid, dipicolinic acid (DPA), ethanolaminediacetic acid, ethanoldiglycine (EDG), ethionine, ethylenediamine (EDA), ethylenediaminediglutaric acid (EDDG), ethylenediaminedi(hydroxyphenylacetic acid (EDDHA), ethylenediaminedipropionic acid (EDDP), ethylenediaminedisuccinate (EDDS), ethylenediaminemonosuccinic acid (EDMS), ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetrapropionic acid (EDTP), ethyleneglycolaminoethylestertetraacetic acid (EGTA), gallic acid, glucoheptonic acid, gluconic acid, glutamicaciddiacetic acid (GLDA), glutaric acid, glyceryliminodiacetic acid, glycinamidedisuccinic acid (GADS), glycoletherdiaminetetraacetic acid (GEDTA), 2-hydroxyethyldiacetic acid, hydroxyethylenediaminetriacetic acid (HEDTA), hydroxyethyldiphosphonic acid (HEDP), 2-hydroxyethylimino diacetic acid (HIMDA), hydroxyiminodiacetic acid (HIDA), 2-hydroxy propylene diamine disuccinic acid (HPDDS), iminodiacetic acid (IDA), iminodisuccinic acid (IDS), itaconic acid, lauroyl ethylene diamine triacetic acids (LED3A), malic acid, malonic acid, methylglycinediacetate (MGDA), methyliminodiacetic acid (MIDA), monoethanolamine, nitrilotriacetic acid (NTA), nitrilotripropionic acid (NPA), N-phosphonomethyl glycine (glyphosate), propyldiamine tetraacetic acid (PDTA), salicylic acid, serinediacetic acid (SDA), sorbic acid, succinic acid, sugars, tartaric acid, tartronic acid, triethanolamine, triethylenetetraamine, triethylene tetraamine hexaacetic acid (TTHA), and combinations thereof. In an exemplary embodiment, the chelating agent is EDTA, HEDTA, EDG, EDDS, GLDA MGDA, isomers thereof, and combinations thereof.

Other suitable chelating agents include aminopolycarboxylic acid, amines, amides, phosphonic acid and combinations thereof. Amino acids can also be used as chelating agents in the present invention. Suitable amino acids include alanine, arginine, asparagine, aspartic acid, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, proline, serine, threonine, tyrosine, valine, and combinations thereof.

Other suitable chelating agents that can be used in the herbicidal compositions of the present invention include beet molasses, carboxylic acids and the salts thereof, salicylic acid and salts thereof, such as ammonium salicylate, citric acid, and combinations thereof.

The chelating agent of the present invention can also be added to the herbicidal composition in a variety of forms, alone, or in combination. In one embodiment, it can be a free acid. In another embodiment the chelating agent can be a salt. Preferably, in this embodiment, the chelating agent is added as a sodium salt, potassium salt, calcium salt, ammonium salt, amine salt, amide salt, and combinations thereof. In another embodiment, the chelating agent can be added as an alkali metal chelate, including calcium and magnesium. Other suitable metal chelates are described above with respect to the metal component.

The end-use concentration of these ingredients of the herbicidal compositions of the present invention can vary depending on the form of the metal component and the chelating agent. When referring to the amount, e.g., concentration and molar ratio, of the metal component in the composition, the amount is based on the amount of metal ions present within the metal component.

Where the selective herbicide composition includes a metal salt and a chelating agent, the concentration of the metal ion and the chelating agent can vary significantly. By way of non-limiting example, the concentration of metal applied to the plant can be in the range of about 0.01 and 5% by weight, and more preferably about 0.05 to 2% by weight, while the concentration of the chelating agent applied to the plant can be in the range of about 0.1 to 10% by weight, and more preferably about 0.2 to 5% by weight. The molar concentration of each ingredient can also vary. Thus, the molar ratio of metal to chelating agent can be substantially equal to one, greater than one, substantially greater than one, less than one, or substantially less than one. More preferably, the molar ratio of metal to chelating agent is in the range of about 0.05:1 to 20:1, and more preferably is about 0.2:1 to 5:1.

Where the composition includes a metal salt and a metal chelate, on the other hand, the metal is preferably present at a molar amount greater than the amount of chelating agent. In an exemplary embodiment, the concentration of metal ions applied to the plant is preferably in the range of about 0.01 to 5.0% by weight, and more preferably about 0.05 to 2.0% by weight, while the concentration of chelating agent(s) applied to the plant is about 0.1 to 10.0% by weight, and more preferably between 0.2 to 5.0% by weight. The molar concentration of each ingredient can also vary. Preferably, the molar ratio of metal to chelating agent is in the range of about 1.0:0.05 to 1.0:1.0, and more preferably is about 1.0:0.1 to 1.0:1.0.

In another embodiment, the composition can include a metal chelate and a chelating agent. While the amount can vary, in this embodiment the chelating agent is present at an amount greater than an amount of metal. In an exemplary embodiment, the concentration of metal applied to the plant is preferably in the range of about 0.01 to 5.0% by weight, and more preferably about 0.05 to 2.0% by weight, while the concentration of the chelating agent applied to the plant is about 0.1 to 10.0% by weight, and more preferably between 0.2 to 5.0% by weight. In yet another embodiment, the composition can include one or more metal chelates. While the amount can vary, the concentration of metal applied to the plant is preferably in the range of about 0.1 to 5.0% by weight, and more preferably about 0.1 to 2.0% by weight.

Besides the above ingredients, a variety of other components can be added to the selective herbicide compositions. By way of non-limiting example, these additives can include fertilizers, growth regulators, amino acids, additional herbicides, thickening agents, dyes and combinations thereof.

A variety of fertilizers may be added to the herbicidal composition of the present invention. Preferably, the fertilizer is a nitrogen-containing fertilizer that is effective to promote the rapid growth of grass, thereby allowing the grass to shade and out-compete the damaged weeds. The end-use concentration of added fertilizer(s) can vary, but preferably, the concentration of fertilizer is in the range of about 0.1 to 5% by weight.

A variety of growth regulators may also be added to the herbicidal composition of the present invention. By way of non-limiting example, the growth regulators added to the herbicidal compositions can include maleic hydrazide (MH), cycocel (2-chloroethyl-trimethyl ammonium chloride), auxins, and combinations thereof. The end-use concentration of the additional growth regulators can vary, but preferably, the concentration is between about 100 ppm and 2% by weight.

The herbicidal compositions of the present invention can also include natural growth regulators, such as for example, salicylic acid, salts of salicylic acid including ammonium salicylate, jasmonates, ethylene, auxins, gibberellins, cytokinins, abscisic acid, and combinations thereof. The end-use concentration of these natural growth regulators can vary, but preferably, the concentration is between about 10 ppm and 5% by weight.

In addition to the selective herbicides disclosed herein, the herbicidal compositions of the present invention can include other herbicides as a co-active ingredient. The co-active ingredients that can be added as additional herbicides include glyphosate, glufosinate, fatty acids and salts thereof; urea, sodium, borax, copper sulfate, carboxylic acids and the salts thereof, ammonium salts, and combinations thereof. The end-use concentration of the additional herbicide(s) can vary, but preferably, the concentration is in the range of about 100 ppm to 5% by weight.

Furthermore, a variety of thickening agents may be added to the herbicidal compositions disclosed herein. Preferably, these thickening agents include Rhodopol 23 (Rhone Poulenc), VanGel B (R. T. Vanderbilt), Kelzan S (Merck & Co.), guar gum, propylene glycol, glycerol, and combinations thereof. The end-use concentration of added thickening agent(s) can vary, but preferably, the concentration is in the range of about 0.01 to 1% by weight.

Other additives may be included in the herbicidal compositions disclosed herein. By way of non-limiting example, a herbicidal composition according to the present invention can include humectants, antioxidants, stabilizing agents, wetting agents, herbicide synergists, sequestrants, and combinations thereof. Suitable humectants include, for example, propylene glycol, glycerin, beet molasses, and combinations thereof. Suitable antioxidants include, for example, citric acid, while suitable stabilizing agents include citric acid, ammonium salts, and combinations thereof Suitable wetting agents include, for example, carboxylic acids and the salts thereof and silicone polymers such as Silwet 77 (Witco Corp, CT, USA). Suitable herbicide synergists and suitable sequestrant additives include, for example, ammonium salts. The end-use concentration of these additives may vary, but preferably, the concentration is between about 0.1 and 5% by weight.

In use, the formulation of the selective herbicide of the present invention can vary. Preferably, the herbicidal compositions are formed as a ready-to-use composition, a liquid concentrate, or a dry concentrate. The solvents used in the ready-to-use liquid composition and liquid concentrate forms can vary. Preferably, the solvent is a poor wetting agent on plant leaves, essentially equal to that of water. Grass leaves are often vertical and hard to wet, whereas many weeds, such as the dandelion, are horizontal and easy to wet. Solutions that are poor wetting agents are advantageous because they tend to bead up and run off of grass leaves, while spreading onto leaves of the horizontal weeds, such as the dandelion. More preferably, the solvent(s) used in the formulation of the disclosed herbicidal compositions are propylene glycol, glycerin, alcohols such as tetrahydrofurfuryl alcohol (THFA) and combinations thereof.

The pH of the herbicidal solution can vary, but preferably, the herbicidal compositions of the present invention are effective over a wide range of pH values. More preferably, the pH of the herbicidal compositions of the present invention is between about 1.5 and 10. After the formulation has been prepared, the pH of the solution can be measured and adjusted as necessary. The pH values can be measured using standard pH meters, with glass bulb electrodes.

A typical ready-to-use (RTU) formulation according to one embodiment of the present invention is FeEDTA RTU with 0.2% iron. The ingredients are as follows:

Ingredient Concentration by weight (%) Water 96.75% Na₄EDTA 1.80% Fe(NO₃)₃•9H₂O 1.45%

The RTU formulation is prepared by adding water to a vessel, and adding Na₄EDTA the water while stirring. Once dissolved, the ferric nitrate is added, followed by additional stirring to dissolve the ferric nitrate. This solution can then be sprayed onto areas of lawn and dandelion using a hand sprayer, at a rate of 100 ml/m².

The composition of the present invention can be applied to a variety of undesired vegetation in both residential and commercial plant or crop areas. Preferably, the herbicidal compositions are effective to control weeds and unwanted plants, including dicotyledonous plants, monocotyledonous plants, conifers, cycads, ferns, horsetails, mosses, liverworts, and algae. It is very effective against common weeds such as dandelions (Taraxacum officinale), daisies (Bellis perennis), and chickweed (Stellaria media).

The following non-limiting examples serve to further describe the invention. Unless otherwise specified, all of the iron solutions were made using the same molar concentration of iron ion as chelating agent. All of the outside tests were done on areas of mixed grass and dandelions that were at least 2 months old. For the greenhouse tests, dandelions were grown in a commercial greenhouse mix, using supplemental lighting and heating. Each plant was grown in a 2¼ inch pot to a minimum diameter of 20 cm. All of the solutions were sprayed onto the plants at a rate of 100 ml/m². The ferrous sulfate formulations that were used in examples 1, 2, 8 and 9 contained 1% iron (180 mM), 18 mM EDTA, 1% citric acid and 0.5% urea. In all of the examples, the amount of iron is identified in brackets as the percent iron on a weight basis.

Killex® (Green Cross, Ontario, Canada) is a commonly used selective lawn herbicide and was included in several field tests as a standard. Killex contains 2,4-D (9.5%), mecoprop (5%) and dicamba (0.9%). The product was diluted 6 ml into 1 L of water solution and applied at rate of 200 ml/m², as per label instructions.

All plant damage was assessed using a qualitative rating scale from 0 to 9.

0 No damage 1 Trace of damage 2 Trace to slight damage 3 Slight damage 4 Slight to moderate damage 5 Moderate damage 6 Moderate to severe damage 7 Severe damage 8 Very severe damage 9 Plant dead

A damage rating of “4” or higher may be high enough to control undesired plants.

Example 1 Field Dandelion and Turf Test of Iron Chelates

All of the iron chelates were sprayed once at 0.2% Fe⁺³ (35.8 mM), at a volume of 100 ml/m² onto 0.5 m² areas of mixed grass and dandelions. The spraying of the test was followed by 2 days of rain-free weather. Observations were made 5 days after spraying.

Grass Damage Dandelion Damage pH (0 to 9) (0 to 9) FeEDDS (0.2% Fe⁺³) 7.5 3 4.5 FeEDTA (0.2% Fe⁺³) 7.5 1 8.3 FeHEDTA (0.2% Fe⁺³) 7.5 0 8.9 FeSO₄ (1% Fe⁺²) 2.5 7 6.3 Untreated 0 0.0

Example 2 Field Grass and Dandelion Test of FeEDDS and FeHEDTA at pH 3 and 7

The FeEDDS and FeHEDTA solutions contained 0.2% Fe⁺³ (35.8 mM). The ferrous sulfate contained 1% Fe⁺² (179.1 mM). The solutions were sprayed at a rate of 0.1 L/m² onto 2 plots of 0.5 m² of mixed grass and dandelions. Observations were made 4 days after spraying.

Grass Damage Dandelion Damage pH (0 to 9) (0 to 9) FeEDDS (0.2% Fe⁺³) 3.0 2.0 5.5 FeEDDS (0.2% Fe⁺³) 7.0 1.0 4.0 FeHEDTA (0.2% Fe⁺³) 3.0 0.0 7.0 FeHEDTA (0.2% Fe⁺³) 7.1 1.0 7.5 FeSO₄ (1% Fe⁺²) 2.6 7.0 7.0 Untreated 0.0 0.0

Example 3 Combinations of FeSO4, EDTA, EDDS and MH, at pH 6 and 3, on Dandelions and Grass

This test investigated the effect of 10% chelation and pH on potted grass and dandelions. All of the solutions contained 10% ferrous sulfate heptahydrate, resulting in a Fe⁺² concentration of 2% (358.1 mM). EDTA and EDDS were added at 1/10^(th) of the iron molar concentration (35.8 mM). MH was added 1%. The dandelions and turf grasses were sow in separate pots 3 weeks prior to the start of the test.

The plants were re-sprayed after 9 days.

Plant Damage Plant Death (0 to 9) (%) 3 Days After Second Spray pH Grass Dandelion Grass Dandelion FeSO₄ (2% Fe⁺²) 6 0 6.0 0 17 FeSO₄ + MH (0.2% Fe) 6 0 7.0 0 30 FeSO₄ + EDTA (0.2% Fe) 6 0 8.3 0 87 FeSO₄ + EDDS (0.2% Fe) 6 0 7.3 0 69 FeSO₄ + MH + EDTA 6 0 8.5 0 89 (0.2% Fe) FeSO₄ + MH + EDDS 6 4 7.0 0 56 (0.2% Fe) FeSO₄ (0.2% Fe) 3 4 8.2 0 76 FeSO₄ + EDTA (0.2% Fe) 3 1 9.0 0 100 FeSO₄ + EDDS (0.2% Fe) 3 0 8.7 0 90 Untreated n/a 0.0 0 0 0

Example 4 Effect of pH on FeHEDTA Applied to Greenhouse Dandelions

This test compared the effects of FeHEDTA at a range of pH values to potted, greenhouse-grown dandelions. All of the solutions were applied at 0.2% Fe⁺³ (35.8 mM). Ammonium sulfate was added at 2%. The plants were re-sprayed after 8 days.

Plant Damage (0 to 9) Dead (#/10) Days After Spraying 7 8 + 5 8 + 5 FeHEDTA pH 3 (0.2% Fe) 3.2 6.8 5 FeHEDTA pH 5 (0.2% Fe) 2.6 5.4 3 FeHEDTA pH 7 (0.2% Fe) 1.9 5.1 2 FeHEDTA pH 9 (0.2% Fe) 2.0 3.6 1 FeHEDTA pH 11 (0.2% Fe) 3.8 6.6 5 FeHEDTA pH 3 + NH₄SO₄ 3.8 7.9 6 (0.2% Fe) Untreated 0.0 0.0 0

Example 5 Effect of Additives on FeEDDS (0.4% Fe⁺³) on Dandelions

The literature identifies many compounds that can chelate iron. This test evaluated combinations of these compounds with EDDS sprayed onto greenhouse grown dandelions. Maleic hydrazide (MH) was included to investigate the effect of a growth inhibitor on the response of the plant to iron.

All of the additives, except MH and beet molasses, were applied at the same molar concentration as the iron (71.6 mM). NaEDDS was used at twice the molar concentration of iron (143.3 mM). All of the solutions were adjusted to pH 5.1, except as noted, using sodium carbonate. The plants were re-sprayed 7 days after the first spray.

Dead or Plant Damage Dying (0 to 9) (#/10) Days After Spraying pH 7 7 + 7 7 + 7 FeEDDS (0.4% Fe⁺³) (A) 5.2 5.8 3.8 3 (A) “pH 9” (0.4% Fe⁺³) 8.7 5.9 5.6 3 (A) + ascorbic acid (0.4% Fe⁺³) 5.1 5.7 4.5 3 (A) + citrate acid (0.4% Fe⁺³) 5.5 7.7 5.6 4 (A) + malic acid (0.4% Fe⁺³) 5.1 7.0 4.1 2 (A) + salicylic acid (0.4% Fe⁺³) 5.1 7.4 7.7 8 (A) + succinic acid (0.4% Fe⁺³) 5.3 6.5 5.3 1 (A) + tartaric acid (0.4% Fe⁺³) 5.1 7.3 5.2 4 (A) + NH₄SO₄ (0.4% Fe⁺³) 5.2 4.9 5.2 4 (A) + beet molasses 4% (0.4% Fe⁺³) 5.2 7.1 7.5 6 (A) + MH 0.2% (0.4% Fe⁺³) 5.2 7.1 7.0 6 (A) + MH 0.5% (0.4% Fe⁺³) 5.2 7.2 8.3 8

Example 6 Effect of Various Fe Chelates on Dandelion Phytotoxicity

This test compared EDG (ethanol diglycine) and EDDS at 0.4% Fe+3 (71.6 mM), with HEDTA 0.2% Fe+3 (35.8 mM). FeEDDS and FeEDG were made with 100% excess chelating agent. FeHEDTA was made with 10% excess chelating agent. The solutions were sprayed onto greenhouse grown dandelions. The plants were resprayed after 7 days.

Plant Damage Dead Plants (0 to 9) (#/10) Days After Spraying pH 7 7 + 5 7 + 5 FeEDG (0.4% Fe⁺³) 8.3 1.4 6.4 1 FeEDDS (0.4% Fe⁺³) 5.5 5.0 8.6 8 FeHEDTA (0.2% Fe⁺³) 5.5 1.3 8.1 3 Untreated 0.0 0.0 0

Example 7 Potassium Nonanoate KC9 with FeHEDTA on Greenhouse Dandelions

This test compared the damaged caused by combinations of fatty acid and FeHEDTA. FeHEDTA was used at a concentration to 35.8 mM. The treatment with 0.1% Fe contained twice the molar amount of chelating agent as iron. The treatment with 0.2% iron contained the same molar amount of chelating agent as iron Potassium nonanoate (KC9) was used at 0.84%. The plants were re-sprayed 8 days after the first spray.

Plant Damage Dead Plants (0 to 9) (#/10) [Fe⁺³] [HEDTA] Days After Spraying (mM) (mM) pH 7 8 + 5 8 + 5 KC9 0.0 0.0 7.7 0.0 0.6 0 KC9 + FeHEDTA (0.1% Fe⁺³) 18.0 35.8 7.8 8.1 9.0 10 KC9 + FeHEDTA (0.2% Fe⁺³) 35.8 35.8 7.8 5.9 7.6 7 FeSO₄ (0.2% Fe⁺²) 35.8 0.0 2.4 0.8 0.2 0 FeSO₄ (1% Fe⁺²) 179.1 0.0 2.1 4.4 7.2 5 FeSO₄ (2% Fe⁺²) 358.1 0.0 1.9 6.2 8.4 8 Untreated 0.0 0.0 0

Example 8 Field Daisy Test of Iron Solutions with Added EDTA and Propylene Glycol

Field areas with 10 cm to 20 cm areas of daisy plants (Bellis perennis BELPE) were sprayed with various 2% Fe⁺² iron (358 mM) solutions at a rate of 0.5 L/m². The areas were assessed 6 days after spraying.

pH Daisy Mortality (%) FeSO₄ (2% Fe⁺²) 2.2 6 FeSO₄ + NaEDTA (2% Fe⁺²) 2.6 35 FeSO₄ + PG (2% Fe⁺²) 2.2 6 FeSO₄ + PG + NaEDTA (2% Fe⁺²) 2.6 60 Untreated 0

Example 9 Restoring Dandelion and Dock Infested Lawns with Iron Solutions

This test compared the activity of ferrous sulfate and a solution of ferrous sulfate, citric acid (2%), urea (1%) and EDTA (1.5%). 0.5 m² areas of turf were sprayed on June 25^(th) and July 7^(th), with observations made on July 13^(th). At the time of the first spraying, grass covered less than 1% of the areas, with dandelions (Taraxacum officinale) and dock (Rumex crispus) covering the remaining plot areas. The dandelions had leaves 8 to 10 cm long. Iron solutions were applied at 1% Fe⁺³ (179 mM). Na₄EDTA was added to the ferrous sulfate solution at 1.5% (36 mM). The molar level of EDTA is 1/10 that of the iron ions. Citric acid was used at 2% and urea at 1%. The urea is added as a nitrogen fertilizer source to encourage the growth of the grasses.

The plot coverage by various plant species remained unchanged in the untreated areas. The “ferrous sulfate only” treatment reduced the area covered by dock and increased the area covered by turf grasses. However, it did not appear to reduce the area covered by dandelions. The area treated with the ferrous sulfate with added EDTA, citrate and urea showed a dramatic increase in grass coverage, and a reduction in the dandelion and dock coverage. In the area treated with ferrous sulfate with added EDTA, citrate and urea, the dock and dandelions died, leaving bare soil exposed. Grass seed can be re-sown in treated areas 7 days after treatment with no ill effects.

Observations After 18 days Grass Plot Area Covered (%) By: Damage Grass Dandelion Dock Bare Soil (0 to 9) Untreated 1 70 29 0 0 FeSO₄ (pH 2.4) 20 65 14 1 1 (1% Fe⁺²) FeSO₄ (1%) + EDTA, 45 15 10 30 1 citrate & urea (pH 2.5) (1% Fe)

Example 10 Evaluation of FeHEDTA with 0.1% and 0.2% Fe⁺³ on Dandelions

This test investigated using 0.1% (17.9 mM) and 0.2% (35.8 mM) iron, as FeHEDTA, to kill potted dandelions. The solutions contained 10% excess chelating agent.

Small (12 cm diameter) to medium (20 cm diameter) sized, greenhouse-grown dandelions were used. These sizes of dandelions are typically found in lawns. The plants were re-sprayed 7 days after the first spray.

These sizes of dandelions are very susceptible to the FeHEDTA.

FeHEDTA Conc. As % iron Dead Dandelions (#/10) Days After Spraying Dandelion Diameter 6 7 + 6 FeHEDTA (0.1% Fe) 12 cm 2 10 FeHEDTA (0.2% Fe) 12 cm 8 10 FeHEDTA (0.1% Fe) 16 cm 1 3 FeHEDTA (0.2% Fe) 16 cm 3 10 FeHEDTA (0.1% Fe) 20 cm 0 3 FeHEDTA (0.2% Fe) 20 cm 1 8

Example 11 Field Test of FeHEDTA, (FeEDDS+Fe MGDA), and Killex to Control Dandelion and Daisy Plants in Lawns

This test investigated the effect of FeHEDTA and a mixture of FeEDDS and FeMGDA on daisy (Bellis perennis), dandelion (Taraxacum officinale) and a turf bentgrass (Agrostis sp.). The chelating agents were used at one and a half times the molar amount of iron. The FeHEDTA solutions contained 0.2% iron (35.8 mM). The commercially prepared FeHEDTA product from the Monterey Chemical Company (CA, USA) was used as a standard. The (FeEDDS+FeMGDA) solutions contained 0.4% iron (71.6 mM) and the same molar amount of EDDS and MGDA. The solutions were made from NaEDDS (Octaquest E30, Octel) and NaMGDA (Trilon M liquid, BASF, Germany). Ammonium sulfate was added at a concentration of 1%. Killex (Solaris ON, Canada) was diluted and applied as per label instructions of 6 ml/L applied at 200 ml/m².

The daisy (0.25 m²) and dandelion (0.5 m²) test plots were in different areas of the bentgrass field. The dandelions were large, averaging 30 cm in diameter. The daisy patches were between 10 and 20 cm in diameter. The plants were sprayed weekly 4 times.

The iron treatments were effective at killing the daisy and dandelion plants and did not cause significant grass damage. The only grass damage that was observed was a minor blackening of some of the leaf tips.

Dandelion Data Plot Area Dandelion Covered by Necrosis Dandelion Plants (%) (%) Days After Start of Test 0 13 21 26 2 9 16 23 FeHEDTA (0.2% Fe) 80 5 10 8 95 98 97 97 FeHEDTA + NH₄SO₄ (0.2% 80 5 8 6 90 95 95 95 Fe) FeHEDTA (Monterey) (0.2% 80 15 12 8 85 96 90 92 Fe) FeEDDS + FeMGDA (0.4% 80 10 10 10 80 98 80 95 Fe) FeEDDS + FeMGDA + 75 10 12 10 85 99 85 95 NH₄SO₄ (0.4% Fe) Killex 85 85 60 25 0 0 35 65 Water 85 80 80 90 0 0 0

Daisy Data Plot Area Covered by Daisy Necrosis Daisy Plants (%) (%) Days After Start of Test 0 13 21 30 2 10 16 23 FeHEDTA (0.2% Fe) 60 1 2 0.5 20 95 98 98 FeHEDTA + NH₄SO₄ 35 1 1 1 35 97 98 99 (0.2% Fe) FeHEDTA (Monterey) 40 10 5 0.5 35 70 92 90 (0.2% Fe) FeEDDS + FeMGDA 55 5 3 4 35 70 90 80 (0.4% Fe) FeEDDS + FeMGDA + 45 7 7 2 30 90 92 90 NH₄SO₄ (0.4% Fe) Killex 60 25 15 1 0 5 25 45 Water 50 40 45 45 0 0 0 0 Turfgrass Data Blackening of Bentgrass (Agrostis) Leaf Tips (0 to 9) Days After Start of Test 1 6 9 16 21 23 30 FeHEDTA (0.2% Fe) 0 0 0 2 0.5 0 0 FeHEDTA + NH₄SO₄ (0.2% Fe) 0 0 0 0.5 0 0 0 FeHEDTA (Monterey) (0.2% Fe) 0 0 0 0.5 0 0.5 0 FeEDDS + FeMGDA (0.4% Fe) 0.5 0.5 2 3 0.5 1 0 FeEDDS + FeMGDA + NH₄SO₄ 0 1 2 2 0.5 1 0 (0.4% Fe) Killex 0 0 0 0 0 0 0 Water 0 0 0 0 0 0 0

Example 12 Effect of FeHEDTA on the Chickweed Scarlet Pimpernel and Dandelion

This test evaluated FeHEDTA with 0.15% and 0.2% Fe for controlling the chickweed scarlet pimpernel (Anagallis arvensis) and dandelion (Taraxacum officinale). The solution contained 1.3 times the molar amount of chelating agent as iron. Field areas of well established chickweed and dandelion (0.5 m²) were sprayed at a rate of 100 ml/m².

FeHEDTA significantly reduced the numbers of dandelions and chickweed plants.

DANDELION Dandelion Plants Survival of Dandelion (#/0.5 m²) Plants (%) Days After Spraying 0 7 day 7/day 0 Untreated 69 69 100% FeHEDTA (0.15% Fe) 57 19 33 FeHEDTA (0.20% Fe) 84 24 29

CHICKWEED Chickweed Plants Survival of Chickweed (#/0.5 m²) Plants (%) Days After Spraying 0 7 day 7/day 0 Untreated 23 23 100% FeHEDTA (0.15% Fe) 15 8 53 FeHEDTA (0.20% Fe) 25 4 16

Example 13 Field Test of FeHEDTA at 0.2% Fe and FeEDDS at 0.4% Fe

This test evaluated FeEDDS (0.4% Fe⁺³) and FeHEDTA (0.2% Fe⁺³) for controlling the weed hairy cat's ear (Hypochoeris radicata), also known as “false dandelion”, grown in areas of mixed grass and Hypochoeris. The iron solutions were sprayed at a rate of 100 ml/m² to 1.0 m² plots. The iron treatments were resprayed after 7 and 14 days. Killex (Solaris ON, Canada) was diluted and applied once as per label instructions of 6 ml /L applied at 200 ml/m².

The Killex treatment did not result in a reduction in the plot area covered by cat's ear, although the plants exhibited severe epinasty symptoms. The grass covered between 15 and 30% of the area over the course of the experiment.

In contrast, the iron treatments eliminated cat's ear from the plots after 3 sprays, even though cat's ear was the predominate weed at the start of the test. The area covered by grass increased 2.5 to 3 fold during the test. None of the treatments caused significant grass phytotoxicity.

Cat's Ear Area Covered by Hairy Cat's Ear (%) Relative Cat's Ear Area (Start = 100%) Days After Start of Test 0 6 8 14 18 0 6 8 15 18 FeHEDTA 65 20 20 5 0 100 31 31 8 0 (0.2% Fe) FeEDDS 55 20 25 10 0 100 36 45 19 0 (0.4% Fe) Killex 55 60 70 70 53 100 109 127 127 96 Untreated 64 55 60 57 70 100 86 94 89 109

Grass Area Covered by Hairy Grass (%) Relative Grass Area (Start = 100%) Days After Start of Test 0 6 8 15 18 0 6 8 15 18 FeHEDTA 15 47 40 50 46 100 313 267 333 307 (0.2% Fe) FeEDDS 20 49 55 50 50 100 245 275 250 250 (0.4% Fe) Killex 23 20 15 15 30 100 87 65 65 130 Untreated 15 15 15 10 5 100 100 100 67 33

Example 14 Field Dandelion Test of FeHEDTA, FeEDTA, FeEDDS, FeMGDA, and 50:50 Mixtures of Chelate Combinations

Solutions were made of FeHEDTA (0.2% Fe), FeEDTA (0.2% Fe), FeEDDS (0.4% Fe), and FeMGDA (0.4% Fe). For the combinations, these 4 solutions were mixed together in a 1:1 ratio. The plots (0.25 m²) were sprayed 3 times at weekly intervals at a rate of 0.1 L/m². The plots contained a mixture of dandelion and hard fescue turfgrass.

All of the iron chelate solutions provided dandelion control that was equal to or better than that provided by Killex. No phytotoxicity was observed on the turfgrass.

Dandelion Area Covered by Dandelion Dandelion (%) Necrosis (%) Days After Start of Test 0 6 15 21 33 11 18 FeHEDTA (0.2% Fe) 40 20 8 2 97 95 97 FeEDTA (0.2% Fe) 30 10 7 1 90 90 98 FeEDDS (0.4% Fe) 25 20 5 1 45 90 70 FeMGDA (0.4% Fe) 30 17 12 2 80 85 99 FeHEDTA + FeEDTA (0.2% Fe) 30 9 5 2 98 90 95 FeHEDTA + FeEDDS (0.3% Fe) 35 15 12 3 97 80 97 FeHEDTA + FeMGDA (0.3% Fe) 25 10 5 1 95 98 99 FeEDDS + FeMGDA (0.4% Fe) 30 9 10 3 95 90 98 FeEDDS + FeEDTA (0.3% Fe) 30 20 13 3 80 70 96 FeEDTA + FeMGDA (0.3% Fe) 30 13 6 2 85 85 98 Killex 40 30 25 10 15 25 50 Untreated 25 20 60 70 0 0 0

Dandelion Dandelion Count Surviving (#/0.25 m²) Dandelions (%) Days After Start of Test 0 6 13 21 6 13 21 FeHEDTA (0.2% Fe) 63 60 40 26 95 63 41 FeEDTA 0.2% Fe 56 33 20 19 59 36 34 FeEDDS 0.4% Fe 53 40 19 16 75 36 30 FeMGDA 0.4% Fe 72 71 43 19 99 60 26 FeHEDTA + FeEDTA 58 37 27 18 64 47 31 (0.2% Fe) FeHEDTA + FeEDDS 67 57 53 21 85 79 31 (0.3% Fe) FeHEDTA + FeMGDA 45 28 19 13 62 42 29 (0.3% Fe) FeEDDS + FeMGDA 59 51 42 20 86 71 34 (0.4% Fe) FeEDDS + FeEDTA (0.3% Fe) 55 55 47 23 100 85 42 FeEDTA + FeMGDA (0.3% Fe) 62 41 32 17 66 52 27 Killex 55 50 38 33 91 69 60 Untreated 49 51 49 53 100 100 100

Example 15 Greenhouse Dandelion Damage of FeEDDS with Various Additives

This test investigated combinations of various chelating agents with FeEDDS. All of the solutions contained 0.4% iron (71.6 mM). The chelating agents were made as sodium salts and added to a solution of FeEDDS. The solutions were sprayed onto greenhouse-grown dandelions at a rate of 100 ml/m². The test was resprayed after 7 days.

All of the solutions were effective at controlling dandelions.

Dandelion Dandelion Dead Necrosis (%) Dandelion (#/20) Days After Start of Test 1 10 7 10 FeEDDS 0.4% Fe (A) 67 96 6 10 (A) + citric 2% (0.4% Fe) 89 98 5 14 (A) + gluconic 2% (0.4% Fe) 87 98 7 11 (A) + lactic 2% (0.4% Fe) 84 98 3 12 (A) + malonic 2% (0.4% Fe) 90 99 10 18 (A) + malic 2% (0.4% Fe) 93 98 11 17 (A) + glycine 2% (0.4% Fe) 84 97 7 18 Untreated 0 0 0 0

Example 16 Comparison of Different Salts of EDTA on Greenhouse Dandelion Mortality

This test investigated various metal chelates. All chelate solutions contained 0.4% metal ions with 10% excess chelator, and were adjusted to pH 7. For the combinations, these 4 solutions were mixed together in a 1:1 ratio. The solutions were sprayed onto greenhouse grown dandelions at a rate of 100 ml/m². The test was re-sprayed after 7 days.

FeEDTA is a better herbicide than Al EDTA, Cu EDTA and ZnEDTA. Also 1 to 1 mixtures of Fe EDTA with other metal chelates caused the same damage as FeEDTA.

Dandelion Dead Dandelion (#/20) Days After Start of Test 7 10 Fe EDTA (0.4% Fe) 10 17 Al EDTA (0.4% Al) 0 0 Cu EDTA (0.4% Cu) 0 4 Zn EDTA (0.4% Zn) 0 0 (Fe + Al) EDTA (0.2% Fe + 0.2% Al) 8 17 (Fe + Cu) EDTA (0.2% Fe + 0.2% Cu) 3 16 (Fe + Zn) EDTA (0.2% Fe + 0.2% Zn) 0 14 FeCl₃ (0.4% Fe) 0 0 Untreated 0 0

In another embodiment, the present invention provides a more environmentally compatible selective herbicide that is effective to remove unwanted broadleaf weeds while leaving grasses and other desirable plants unaffected. The composition comprises a water-soluble auxin-type herbicide and a chelating agent that is complexed with at least one transition metal. The composition is useful in a method of treating undesired vegetation in which the composition is provided and vegetation is contacted with a herbicidally effective amount of the composition such that unwanted vegetation is controlled, while desired vegetation is unaffected. The sources of the chelating agent and the transition metal that form the complex can vary, as described below. In another embodiment, the composition used to selectively kill unwanted vegetation is an environmentally compatible selective herbicide composition comprising the combination of a water-soluble selective auxin-type herbicide and an ethylenediaminedisuccinic compound. One characteristic of the compositions and the methods disclosed herein is the enhanced and/or synergistic activity that is achieved when the composition is applied to vegetation to control undesired vegetation.

In one aspect, the metal component used to form the complex of the present invention includes a transition metal. Suitable transition metal ions include, for example, copper ions, iron ions, manganese ions, zinc ions, and combinations thereof. In an exemplary embodiment, the metal component includes an iron ion, which can be present in a variety of ionic states. By way of non-limiting example, iron ions used in the present invention can be added as Fe⁺² ions, Fe⁺³ ions, and mixtures thereof.

The metal component of the present invention can be added in a variety of forms. In one embodiment, the metal ions can be added as a metal salt. Exemplary metal salts include metal chlorides, metal sulfates, metal nitrates, metal citrates, metal phosphates, metal sulfides, metal sulfites, metal succinates, metal gluconates, metal lactates, metal formates, metal nitrites, metal salicylates, metal carboxylic acids, and combinations thereof.

Another component of the herbicidal composition that forms a complex with a transition metal is a chelating agent. A variety of chelating agents can be used in the water-soluble selective auxin-type herbicide compositions of the present invention to form a metal chelate. By way of non-limiting example, suitable chelating agents include aconitic acid, alanine diacetic acid (ADA), alkoyl ethylene diamine triacetic acids (e.g., lauroyl ethylene diamine triacetic acids (LED3A)), aminotri (methylenephosphonic acid) (ATMP), asparticaciddiacetic acid (ASDA), asparticacidmonoacetic acid, diamino cyclohexane tetraacetic acid (CDTA), citraconic acid, citric acid, 1,2-diaminopropanetetraacetic acid (DPTA-OH), 1,3-diamino-2-propanoltetraacetic acid (DTPA), diethanolamine, diethanol glycine (DEG), diethylenetriaminepentaacetic acid (DTPA), diethylene triamine pentamethylene phosphonic acid (DTPMP), diglycolic acid, dipicolinic acid (DPA), ethanolaminediacetic acid, ethanoldiglycine (EDG), ethionine, ethylenediamine (EDA), ethylenediaminediglutaric acid (EDDG), ethylenediaminedi(hydroxyphenylacetic acid (EDDHA), ethylenediaminedipropionic acid (EDDP), ethylenediaminedisuccinate (EDDS), ethylenediaminemonosuccinic acid (EDMS), ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetrapropionic acid (EDTP), ethyleneglycolaminoethylestertetraacetic acid (EGTA), gallic acid, glucoheptonic acid, gluconic acid, glutamicaciddiacetic acid (GLDA), glutaric acid, glyceryliminodiacetic acid, glycinamidedisuccinic acid (GADS), glycoletherdiaminetetraacetic acid (GEDTA), 2-hydroxyethyldiacetic acid, hydroxyethylenediaminetriacetic acid (HEDTA), hydroxyethyldiphosphonic acid (HEDP), 2-hydroxyethyl imino diacetic acid (HIMDA), hydroxyiminodiacetic acid (HIDA), 2-hydroxy propylene diamine disuccinic acid (HPDDS), iminodiacetic acid (IDA), iminodisuccinic acid (IDS), itaconic acid, lauroyl ethylene diamine triacetic acids (LED3A), malic acid, malonic acid, methylglycinediacetate (MGDA), methyliminodiacetic acid (MIDA), monoethanolamine, nitrilotripropionic acid (NPA), N-phosphonomethyl glycine (glyphosate), propyldiamine tetraacetic acid (PDTA), salicylic acid, serinediacetic acid (SDA), sorbic acid, succinic acid, sugars, tartaric acid, tartronic acid, triethanolamine, triethylenetetraamine, triethylene tetraamine hexaacetic acid (TTHA), and combinations thereof. In an exemplary embodiment, the chelating agent is HEDTA, EDTA, CDTA, EDDS, GLDA MGDA, IDS, EDG, DTPA, isomers thereof, and combinations thereof.

Other suitable chelating agents that can be used in the herbicidal compositions of the present invention to form the metal chelate include citric acid, salicylic acid and salts thereof, such as ammonium salicylate, and combinations thereof Amino acids can also be used as chelating agents in the present invention. Suitable amino acids include alanine, arginine, asparagine, aspartic acid, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, proline, serine, threonine, tyrosine, valine, and combinations thereof

The chelating agent can be present in the herbicidal composition in a variety of forms, alone or in combination. In one embodiment, the chelating agent can be in the form of a free acid. In another embodiment the chelating agent can be a salt. Exemplary salt forms of the chelating agent include sodium salts, potassium salts, calcium salts, ammonium salts, amine salts, amide salts, magnesium salts, and combinations thereof. The actual compounds that can be used to form this component of the herbicidal composition include those chelating agents described above.

Suitable water-soluble selective auxin-type herbicides for use with this invention include aminopyralid (4-amino-3,6-dichloropyridine-2-carboxylic acid), clomeprop ((RS)-2-(2,4-dichloro-m-tolyloxy)propionanilide), clopyralid (3,6-dichloro-2-pyridinecarboxylic acid), 2,4-D ((2,4-dichlorophenoxy)acetic acid), dicamba (3,6-dichloro-2-methoxybenzoic acid), dichlorprop ((±)-2-(2,4-dichlorophenoxy)propanoic acid), fluroxypyr ([(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid), MCPA ((4-chloro-2-methylphenoxy)acetic acid), mecoprop ((±)-2-(4-chloro-2-methylphenoxy)propanoic acid), picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid), quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), quinmerac (7-chloro-3-methyl-8-quinolinecarboxylic acid), triclopyr ([(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid), their salts, acids, esters, and combinations thereof.

Some of the water-soluble selective auxin-type herbicide components of the present invention can also be added in a variety of forms. In one embodiment, the auxin-type herbicide can be added as a salt, and exemplary salts include potassium salts, sodium salts, ammonium salts, isopropylamine salts, dimethylamine salts, triethylamine salts, diglycolamine salts, triisopropanolamine salts, triisopropanolammonium salts, monoethanolamine salts, diethanolamine salts, and combinations thereof In another embodiment, the herbicide can be added as an acid. In yet another embodiment, the herbicide can be added as an ester such as a butoxyethyl ester, ethylhexyl ester, isooctyl ester, methylheptyl ester, and combinations thereof.

Where the herbicide composition includes a metal salt, a chelating agent, and a water-soluble selective auxin-type herbicide, the concentration of the metal ion, the chelating agent and the herbicide can vary significantly. By way of non-limiting example, the concentration of metal ions applied to the plant should be in the range of about 0.01 to 5% by weight, and more preferably in the range of about 0.05 to 2% by weight; the concentration of the chelating agent applied to the plant can be in the range of about 0.1 to 25% by weight, and more preferably in the range of about 0.2 to 10% by weight, the concentration of the water-soluble selective auxin-type herbicide applied to the plant can be in the range of about 0.00001 to 20% by weight, and more preferably in the range of about 0.00005 to 15% by weight.

In another aspect, the composition comprises a water-soluble selective auxin-type herbicide and an ethylenediaminedisuccinic compound. The ethylenediaminedisuccinic compound can be in the form of an acid or a salt. Exemplary salt forms of this compound include sodium salts, potassium salts, ammonium salts, and combinations thereof. In this embodiment, the sodium, potassium or ammonium ions can be present in the composition at a concentration in the range of about 0.01 to 5% by weight, and more preferably at a concentration in the range of about 0.05 to 2% by weight, while the ethylenediaminedisuccinic compound can be present in the composition at a concentration in the range of about 0.1 to 25% by weight, and more preferably at a concentration in the range of about 0.2 to 10% by weight, when the composition is applied to vegetation. The concentration of the water-soluble selective auxin-type herbicide applied to the plant can be in the range of about 0.00001 to 20% by weight, and more preferably at a concentration in the range of about 0.00005 to 15% by weight.

Besides the ingredients described above, a variety of other components can be added to the herbicide compositions. By way of non-limiting example, these additives can include fertilizers, growth regulators, selective herbicides, thickening agents, dyes, and combinations thereof.

A variety of fertilizers may be added to the herbicidal composition of the present invention. The end-use concentration of added fertilizer(s) can vary, but preferably, the concentration of fertilizer is in the range of about 0.1 to 5% by weight.

A variety of growth regulators may also be added to the herbicidal composition of the present invention. By way of non-limiting example, the growth regulators added to the herbicidal compositions can include maleic hydrazide (MH), cycocel (2-chloroethyl-trimethyl ammonium chloride), and combinations thereof. The end-use concentration of the additional growth regulators can vary, but preferably, the concentration is between about 0.01 and 2% by weight.

The herbicidal compositions of the present invention can also include natural growth regulators, such as ammonium salicylate, jasmonates, ethylene, auxins, gibberellins, cytokinins, abscisic acid, and combinations thereof. The end-use concentration of these natural growth regulators can vary, but preferably, the concentration is in the range of about 0.001 to 5% by weight.

Furthermore, a variety of thickening agents may be added to the herbicidal compositions disclosed herein. Exemplary thickening agents include Rhodopol 23 (Rhodia), VanGel B (R. T. Vanderbilt), Kelzan S (C.P. Kelco), guar gum, propylene glycol, glycerol, and combinations thereof. The end-use concentration of added thickening agent(s) can vary, but preferably, the concentration is in the range of about 0.01 to 1% by weight.

Other additives may be included in the herbicidal compositions disclosed herein as well. By way of non-limiting example, such other additives can include humectants, antioxidants, stabilizing agents, wetting agents, surfactants, herbicide synergists, solvents, sequestrants, and combinations thereof. Suitable humectants include, for example, propylene glycol, glycerin, beet molasses, and combinations thereof. Suitable antioxidants include, for example, citric acid, while suitable stabilizing agents include citric acid, ammonium salts, and combinations thereof. Suitable wetting agents include, for example, carboxylic acids and the salts thereof and silicone polymers such as Silwet 77 (G.E. Co. Advanced Materials Silicones). The end-use concentration of these additives may vary, but preferably, the concentration is in the range of about 0.01 to 5% by weight.

In use, the formulation of the water-soluble selective auxin-type herbicide of the present invention can vary. Preferably, the herbicidal compositions are formed as a ready-to-use composition, a liquid concentrate, a tank-mix, or a dry concentrate. The solvents used in the ready-to-use liquid composition and liquid concentrate forms can also vary and exemplary solvents include propylene glycol, glycerin, alcohols such as tetrahydrofurfuryl alcohol (THFA), and combinations thereof.

The pH of the herbicidal solution can vary, but the herbicidal compositions of the present invention are effective over a wide range of pH values. An exemplary pH is in the range of about 1.5 to 10. After the formulation has been prepared, the pH of the solution can be measured and adjusted as necessary. The pH values can be measured using standard pH meters, with glass bulb electrodes.

An exemplary ready-to-use (RTU) formulation according to one embodiment of the present invention includes FeHEDTA metal chelate with 0.4% iron and 0.6% Killex®. The ingredients used to form this composition are as follows:

Ingredient Concentration by weight (%) Deionized water 95.4% Na₃HEDTA 2.8% FeCl₃ 1.2% Killex ®* 0.6% *Killex ® contains 2,4-D (9.5%), mecoprop (5%) and dicamba (0.9%).

The RTU formulation shown above is prepared by adding deionized water to a vessel, and adding ferric chloride to the water while stirring. Once dissolved, the Na₃HEDTA is added, followed by additional stirring to dissolve the Na₃HEDTA. The pH is then adjusted to between 6 and 8. Lastly, Killex® is added, followed by additional stirring until thoroughly mixed. This solution can then be sprayed onto areas of lawn and weeds using a handheld trigger sprayer, a pump-wand sprayer, or broadcast sprayer, at a rate of about 200 ml/m².

The herbicide compositions of the present invention can be applied to a variety of undesired vegetation in both residential and commercial plant or crop areas. Preferably, the herbicide compositions are effective to selectively control broadleaf weeds growing in grass and turf areas. The herbicidal compositions disclosed herein are very effective against numerous common broadleaf weeds, mosses, liverworts, and algae. Grass and turf areas that are infested with undesired vegetation can be entirely sprayed with a herbicidal composition of the present invention to selectively remove the unwanted vegetation, while leaving the grass, turf and other desired plants undamaged.

One advantageous characteristic of the herbicidal compositions of the present invention is their relatively fast-acting nature. The herbicidal compositions described in this invention show signs of herbicidal activity within days compared to the weeks typically required for known auxin-type herbicides to achieve the same level of activity. In addition, an enhanced and/or synergistic level of herbicidal activity is obtained against the unwanted vegetation with the herbicidal compositions of the current invention, relative to the individual components if used alone. This improvement in herbicidal activity can be seen within days of treatment, lasting up to many weeks after treatment. Furthermore, the improved weed activity that results from the herbicide compositions of the current invention also allows for a reduction in the amount of the auxin-type herbicide that is required to achieve comparable weed control to the full rate of the auxin-type herbicide on its own. Reducing auxin-type herbicide rates while maintaining similar weed control is beneficial for consumers and the environment in general, particularly since some of these auxin-type herbicides have raised health concerns in recent years. Although increased broadleaf weed activity results with the herbicide compositions of the present invention, selectivity is maintained wherein treated grass species remain relatively unaffected, sometimes with less injury seen than when the individual components are applied on their own.

The following non-limiting examples serve to further describe the invention. For the greenhouse tests, plants were grown in a commercial greenhouse mix, using supplemental lighting and heating. Plants were fertilized with an all purpose water-soluble fertilizer mix of 20-20-20 (N-P-K; Plant-Prod®) as needed. All broadleaf weeds were grown individually in a 2¼-inch pot until they were a suitable size for herbicide tests (actual weed size is reported in examples below). Perennial ryegrass was also grown in 2¼-inch pots, however many grass seeds were sown in the pot to simulate a small section of turf. Grass plants were continually trimmed to a height of 4 cm, simulating that of a homeowner's lawn. For field tests, plots ¼ m² in size were marked out in areas containing the targeted broadleaf weed species growing in turf grass. Plots were continually mowed to simulate a homeowner's lawn. All of the tested herbicidal solutions were sprayed onto the plants at a rate of 200 ml/m². In all of the examples, the amounts of the various herbicide components are identified as a percent on a weight basis.

Killex® (Scotts Canada, Ltd., Ontario, Canada) is a commonly used selective lawn herbicide and was used as the commercial herbicide for herbicide combinations. The labeled dilution and application rates for Killex® are 6 ml into 1 L of solution (0.6%) applied at 200 ml/m².

All visual plant damage assessments were made using a quantitative rating scale; percent control relative to the untreated check (0=no effect; 100=plant death).

Example 17

Objective: To evaluate the combination of various iron chelates with Killex® for herbicidal activity and grass injury.

Materials and Methods: This trial was conducted in the greenhouse. Nine pots of white clover and 10 pots of perennial ryegrass were selected for each treatment. Herbicidal solutions were prepared using deionized water. The treatments were applied using a handheld trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 4, 7, and 14 days after application (A4, A7, and A14).

TABLE 1 Plant stages at the commencement of this study. White clover Perennial ryegrass Leaf # 20+ — Plant Height (cm) 17-20 4 Growth Stage flower vegetative

TABLE 2 Phytotoxicity (%) against white clover. Phytotoxicity (%) White Clover A4 A7 A14 Control 0 0 0 FeMGDA 0.4% Fe 4 5 2 FeIDS 0.4% Fe 7 10 13 FeEDTA 0.4% Fe 15 15 6 FeHEDTA 0.4% Fe 22 19 15 Killex ® 0.6% 10 11 28 FeMGDA 0.4% Fe + Killex ® 0.6% 18 20 38 FeIDS 0.4% Fe + Killex ®0.6% 36 37 53 FeEDTA 0.4% Fe + Killex ®0.6% 27 37 39 FeHEDTA 0.4% Fe + Killex ®0.6% 57 66 66

TABLE 3 Phytotoxicity (%) against perennial ryegrass. Phytotoxcity (%) Perennial ryegrass A4 A7 A14 Control 0 0 0 FeMGDA 0.4% Fe 0 0 0 FeIDS 0.4% Fe 6 5 0 FeEDTA 0.4% Fe 4 2 0 FeHEDTA 0.4% Fe 8 7 1 Killex ® 0.6% 1 1 0 FeMGDA 0.4% Fe + Killex ®0.6% 7 5 0 FeIDS 0.4% Fe + Killex ®0.6% 7 5 1 FeEDTA 0.4% Fe + Killex ® 0.6% 4 2 0 FeHEDTA 0.4% Fe + Killex ® 0.6% 5 4 3

Example 18

Objective: To evaluate the combination of FeHEDTA metal chelates with Killex® for herbicidal activity and grass injury.

Materials and Methods: This trial was conducted in the greenhouse. Nine pots of white clover and 10 pots of perennial ryegrass were selected for each treatment. Herbicide solutions were prepared using deionized water. The treatments were applied using a hand-trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 4, 7, and 14 days after application (A4, A7, and A14).

TABLE 4 Plant stages at the commencement of this study. White clover Perennial ryegrass Leaf # 20+ — Plant Height (cm) 15-19 4 Growth Stage vegetative vegetative

TABLE 5 Phytotoxicity (%) against white clover. Phytotoxicity (%) White Clover A4 A7 A14 Control 0 0 0 FeHEDTA 0.4% Fe 27 50 18 Killex ® 0.6% 11 12 28 FeHEDTA 0.4% Fe + Killex ® 0.6% 58 71 73

TABLE 6 Phytotoxicity (%) on perennial ryegrass. Phytotoxicity (%) Perennial ryegrass A4 A7 A14 Control 0 0 0 FeHEDTA 0.4% Fe 2 1 2 Killex ® 0.6% 0 0 0 FeHEDTA 0.4% Fe + Killex ® 0.6% 1 1 1

Example 19

Objective: To evaluate the combination of FeHEDTA metal chelate with Killex® at reduced rates.

Materials and Methods: This trial was conducted in the greenhouse. Ten broadleaf plantain plants and 5 pots of perennial ryegrass were selected for each treatment. Herbicide solutions were prepared using deionized water. The treatments were applied using a hand-trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 7 days after application (A7).

TABLE 7 Plant stages at the commencement of this study. Broadleaf plantain Perennial ryegrass Leaf # 4-7 — Plant Diameter (cm) 25-45 3-5 (height) Growth Stage vegetative vegetative

TABLE 8 Phytotoxicity (%) against broadleaf plantain. A7 Phytotoxicity (%) Killex ® Killex ® Killex ® Killex ® Broadleaf plantain 0% 0.15% 0.3% 0.6% FeHEDTA 0% Fe 0 14 23 24 FeHEDTA 0.1% Fe 9 25 29 36 FeHEDTA 0.2% Fe 10 27 30 43 FeHEDTA 0.4% Fe 22 35 42 53

TABLE 9 Phytotoxicity (%) against perennial ryegrass. A7 Phytotoxicity (%) Killex ® Killex ® Killex ® Killex ® Perennial ryegrass 0% 0.15% 0.3% 0.6% FeHEDTA 0% Fe 0 1 1 1 FeHEDTA 0.1% Fe 1 1 3 2 FeHEDTA 0.2% Fe 1 1 2 1 FeHEDTA 0.4% Fe 2 1 1 1

Example 20

Objective: To evaluate the combination of NH₄—, Na—, K— and Fe-EDDS with Killex® for herbicidal activity and grass injury.

Materials and Methods: This trial was conducted in the greenhouse. Ten broadleaf plantain plants and 10 pots of perennial ryegrass were selected for each treatment. Herbicide solutions were prepared using deionized water. The treatments were applied using a hand-trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 21 days after application (A21).

TABLE 10 Plant stages at the commencement of this study. Broadleaf plantain Perennial ryegrass Leaf # 12-18 — Plant Diameter (cm) 40-50 4-5 (height) Growth Stage flower vegetative

TABLE 11 Phytotoxicity (%) against broadleaf plantain. Phytotoxicity (%) Broadleaf plantain A21 Control 0 NH₄EDDS 2.09% a.e.^(a) 0 NaEDDS 2.09% a.e. 6 KEDDS 2.09% a.e. 6 FeEDDS 0.4% Fe 2 Killex ® 0.6% 29 NH₄EDDS 2.09% a.e. + Killex ® 0.6% 43 NaEDDS 2.09% a.e. + Killex ® 0.6% 59 KEDDS 2.09% a.e. + Killex ® 0.6% 54 FeEDDS 0.4% Fe + Killex ® 0.6% 47 ^(a)abbreviation a.e. = acid equivalent

TABLE 12 Phytotoxicity (%) on LOLPE. Phytotoxicity (%) LOLPE A21 Control 0 NH₄EDDS 2.09% a.e.^(a) 0 NaEDDS 2.09% a.e. 0 KEDDS 2.09% a.e. 0 FeEDDS 0.4% Fe 0 Killex ® 0.6% 0 NH₄EDDS 2.09% a.e. + Killex ® 0.6% 0 NaEDDS 2.09% a.e. + Killex ® 0.6% 0 KEDDS 2.09% a.e. + Killex ® 0.6% 0 FeEDDS 0.4% Fe + Killex ® 0.6% 0 ^(a)abbreviation a.e. = acid equivalent

Example 21

Objective: To evaluate the combination of various Fe chelates with Killex® for herbicidal activity and grass injury.

Materials and Methods: This trial was conducted in the greenhouse. Seven dandelion plants and 10 pots of perennial ryegrass were selected for each treatment. Herbicide solutions were prepared using deionized water. The treatments were applied using a hand-trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 29 days after treatment (A29).

TABLE 13 Plant stages at the commencement of this study. Dandelion Perennial ryegrass Leaf # 15-34 — Plant Diameter (cm) 25-30 3-4 (height) Growth Stage flower vegetative

TABLE 14 Phytotoxicity (%) against dandelion. Phytotoxicity (%) Dandelion A29 Control 0 FeMGDA 0.4% Fe 12 FeIDS 0.4% Fe 28 FeHEDTA 0.4% Fe 24 Killex ® 0.6% 54 FeMGDA 0.4% Fe + Killex ® 0.6% 79 FeIDS 0.4% Fe + Killex ® 0.6% 98 FeHEDTA 0.4% Fe + Killex ® 0.6% 92

TABLE 15 Phytotoxicity (%) on Perennial ryegrass. Phytotoxicity (%) Perennial Ryegrass A29 Control 0 FeMGDA 0.4% Fe 0 FeIDS 0.4% Fe 0 FeHEDTA 0.4% Fe 0 Killex ® 0.6% 0 FeMGDA 0.4% Fe + Killex ® 0.6% 0 FeIDS 0.4% Fe + Killex ® 0.6% 0 FeHEDTA 0.4% Fe + Killex ® 0.6% 0

Example 22

Objective: To evaluate the combination of FeIDS and/or FeHEDTA metal chelates with Killex®.

Materials and Methods: Plots ¼ m² in size were marked out in white clover and Park Lawn (turfgrass mixture comprising of 65% perennial ryegrass, 25% chewings/creeping red fescue and 10% Kentucky bluegrass) area in the field. Herbicide solutions were prepared using deionized water. All treatments were replicated twice. The treatments were applied using a hand trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed on 7 days after treatment (A7).

TABLE 16 Plant stages at the commencement of this study. White clover Park Lawn Leaf #  20+ — Plant Height (cm) 3-12 3-11 Growth Stage vegetative vegetative Coverage (%) 68 33

TABLE 17 Phytotoxicity (%) against white clover. Phytotoxicity (%) White clover A7 Control 0 FeIDS 0.4% Fe 15 FeHEDTA 0.4% Fe 48 FeIDS 0.2% Fe + FeHEDTA 0.2% Fe 38 Killex ® 0.6% 23 FeIDS 0.4% Fe + Killex ® 0.6% 69 FeHEDTA 0.4% Fe + Killex ® 0.6% 91 FeIDS 0.2% Fe + FeHEDTA 0.2% Fe + 85 Killex ® 0.6%

TABLE 18 Phytotoxicity (%) on Park Lawn. Phytotoxicity (%) Park Lawn A7 Control 0 FeIDS 0.4% Fe 0 FeHEDTA 0.4% Fe 3 FeIDS 0.2% Fe + FeHEDTA 0.2% Fe 1 Killex ® 0.6% 0 FeIDS 0.4% Fe + Killex ® 0.6% 0 FeHEDTA 0.4% Fe + Killex ® 0.6% 2 FeIDS 0.2% Fe + FeHEDTA 0.2% Fe + 0 Killex ® 0.6%

Example 23

Objective: To evaluate the combination of Cu—, Mn— or ZnHEDTA metal chelates with KiHex®.

Materials and Methods: This trial was conducted in the greenhouse. Ten white clover plants and 10 pots of perennial ryegrass were selected for each treatment. Herbicide solutions were prepared using deionized water. The treatments were applied using a hand-trigger sprayer at 200 ml/m². All treatments were applied once. Phytotoxicity (%) was assessed 4 and 7 days after treatment (A4 and A7).

TABLE 19 Plant stages at the commencement of this study. White clover Perennial ryegrass Leaf # 20+ — Plant Height (cm) 3-16 2 Growth Stage veg veg

TABLE 20 Phytotoxicity (%) against white clover. Phytotoxicity (%) White clover A4 A7 Control 0 0 CuHEDTA 0.4% Cu 32 62 MnHEDTA 0.4% Mn 9 12 ZnHEDTA 0.4% Zn 4 3 Killex 0.6% 18 23 CuHEDTA 0.4% Cu + Killex 0.6% 46 69 MnHEDTA 0.4% Mn + Killex 0.6% 33 49 ZnHEDTA 0.4% Zn + Killex 0.6% 36 44

TABLE 21 Phytotoxicity (%) on perennial ryegrass. Phytotoxicity (%) Perennial ryegrass A4 A7 Control 0 0 CuHEDTA 0.4% Cu 3 3 MnHEDTA 0.4% Mn 1 1 ZnHEDTA 0.4% Zn 1 0 Killex 0.6% 1 1 CuHEDTA 0.4% Cu + Killex 0.6% 3 2 MnHEDTA 0.4% Mn + Killex 0.6% 2 3 ZnHEDTA 0.4% Zn + Killex 0.6% 2 2

One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety. 

1. A method for selectively treating vegetation, comprising the steps of: providing a herbicidal composition which includes a herbicidally effective amount of an active ingredient in the form of an iron chelate selected from the group consisting of iron hydroxyethylene diaminetriacetate, iron ethylenediamine tetraacetate, iron ethylene diamine disuccinate, iron glutamicacid diacetate, and combinations thereof; and contacting an area of vegetation including weeds, unwanted plants and grasses with a herbicidally effective amount of the composition, such that the weeds and unwanted plants are selectively controlled while the grasses remain substantially unharmed.
 2. The method of claim 1, wherein the active ingredient is iron hydroxyethylenediamine triacetate.
 3. The method of claim 1, wherein the active ingredient is iron ethylenediamine tetraacetate.
 4. The method of claim 1, wherein the active ingredient is iron ethylene diamine disuccinate.
 5. The method of claim 1, wherein the active ingredient is iron glutamicacid diacetate.
 6. The method of claim 1, wherein the composition that is applied to vegetation includes iron that is present in the iron chelate at a concentration in the range of about 0.1 to about 2.0% by weight.
 7. The method of claim 1, wherein the composition that is applied to vegetation includes iron that is present in the iron chelate at a concentration in the range of about 0.08 to about 0.5% by weight.
 8. The method of claim 1, wherein the composition is provided as a dry concentrate that is dissolved in water before application to vegetation.
 9. The method of claim 1, wherein the composition provided is a liquid concentrate that is diluted with water before application to vegetation.
 10. The method of claim 1, wherein the pH of the composition that is applied to vegetation is in the range of about 4 to about
 8. 11. The method of claim 2, wherein the composition that is applied to vegetation includes iron that is present in the iron hydroxyethylene diaminetriacetate at a concentration in the range of about 0.08 to about 0.50% by weight.
 12. The method of claim 3, wherein the composition that is applied to vegetation includes iron that is present in the iron ethylenediamine tetraacetate at a concentration in the range of about 0.08 to about 0.49% by weight.
 13. The method of claim 4, wherein the composition that is applied to vegetation includes iron that is present in the iron ethylene diamine disuccinate at a concentration in the range of about 0.08 to about 0.49% by weight.
 14. The method of claim 5, wherein the composition that is applied to vegetation includes iron that is present in the iron ethylene diamine disuccinate at a concentration in the range of about 0.09 to about 0.53% by weight.
 15. The method of claim 1, wherein the composition that is applied to vegetation has the iron chelate present at a concentration in the range of about 1 to about 2% by weight. 